In processing elongated workpieces, it is often necesary to heat treat the workpieces by heating and then quenching. When the heating is done by induction heating techniques, the quenching operation can be performed by rotating the workpiece in a body of quenching liquid. The present invention relates to this type of processing.
In the past, it was common practice to quench a heated workpiece by mounting the workpiece between axially spaced centers so that the workpiece could be rotated about its central axis. In order to limit transverse deflection, it has been the practice to provide opposed restraining devices, such as rollers. These rollers limited deflection of the workpiece while rotary motion of the workpiece made this process uniform. Rotation of the heated, elongated workpiece provided an additional benefit to the quenching operation by resisting the development of steam pockets at the surface of the workpiece caused by the heated workpiece contacting the quenching liquid.
The rotation and restraint devices were built into a support mechanism for the elongated workpiece. In the past this complex mechanism was movable between a loading position above a quench tank and a lowered position in the quench tank. The workpiece and support mechanism were removed from the quenching liquid after quenching and the workpiece then released from the support mechanism. Providing translation of the support mechanism for the elongated workpiece was expensive and complicated. In addition, providing a mechanism for rotating the workpiece about its central axis and a mechanism for preventing transverse deflection on the movable support mechanism was difficult and required substantial space and bulky support structures.
The disadvantages of the prior art have been overcome by the present invention which provides a quenching device and method using a fixed support mechanism for an elongated workpiece that includes a mechanism to restrain transverse deflection and to rotate the workpiece about its central axis.